The most common adulteration to which wines are subjected is the addition of water: wines having a rich color are frequently mixed by the dealer with lighter wines, and the fraud consummated by adding water. The detection of this adulteration is somewhat difficult, as water is a normal constituent of wine. In Paris the following method is usually employed: As soon as the wine is confiscated, it is ascertained what kinds of wine are manufactured by the inculpated dealer, and a statement obtained from him, giving the proportions of alcohol, etc., contained in the various brands. A wine is then prepared, according to the information received, an estimation of the alcohol contained in the prepared sample made, and the results compared with those furnished by a similar examination of the suspected wine. In case the proportion of alcohol is less in the suspected wine than in the prepared sample, it is evident that a fraudulent adulteration has been committed. If, however, the quantity of alcohol is the same in both wines, it does not necessarily follow that the wine has escaped admixture, since this body may have been added after the adulteration with water. In addition to the estimation of alcohol, it is also necessary to determine the amount of cream of tartar (bitartrate of potassa) present, as the proportion of this salt would be sensibly decreased by the addition of alcohol and water to the wine. This fraud could, however, be disguised by subsequently adding the proper amount of cream of tartar. It is also well to ascertain if two equal quantities of the prepared sample and the wine under examination require the same amount of solution of hypochlorite of lime for decolorization. In case the suspected wine has been adulterated, the quantity of hypochlorite solution used will be less than the amount necessary to decolorize the prepared wine. Foreign coloring matter may be added by the adulterator, but this fraud is easily detected by adding potassa to the sample: if its coloration is natural, a green tint is produced; whereas, if foreign matter has been introduced, the wine assumes various other colors upon the addition of the alkali.[V] [V] _Cotlini_ (_Ann. du genie civil_, No. 3, 1873) states that the following reactions occur when artificially colored wines are heated with potassa: Pure wine no precipitate greenish hue Elderberry violet " Beet-sugar red " Logwood red violet-red " Privet violet-blue " Turmeric light-blue " According to _M. de Cherville_ (_Quar. Jour. Sc._), a bright violet coloration is produced in the above test, if litmus be present. Fuchsin is separated by treatment with subacetate of lead and addition of amylic alcohol (_Jour. de Ph. et de Ch. Mar. 1873_).--_Trans._